Motor vehicle differentials have been proposed which include a cup-shaped carrier and differential pinions and side gears in the carrier. Typically, the open end of the cup-shaped carrier is closed by a disc-shaped ring gear bolted to the open end of the carrier and defining the drive input member of the differential. Other differentials have been proposed in which a unitary plastic separator is disposed between the carrier and each of the side gears and differential pinions and defines the thrust bearings between the gears and the carrier. A method according to this invention of assembling a differential includes novel steps for simplifying and facilitating assembly of a differential having a cup-shaped carrier and a unitary plastic separator.